LTM4602HV 6A, 28V High Effi ciency IN DC/DC µModule FEATURES DESCRIPTIOU ■ Complete Switch Mode Power Supply The LTM®4602HV is a complete 6A, DC/DC step down ■ Wide Input Voltage Range: 4.5V to 28V power supply with up to 28V input operation. Included ■ 6A DC, Typical 8A Peak Output Current in the package are the switching controller, power FETs, ■ 0.6V to 5V Output Voltage inductor, and all support components. Operating over ■ 1.5% Output Voltage Regulation an input voltage range of 4.5V to 28V, the LTM4602HV ■ Ultrafast Transient Response supports an output voltage range of 0.6V to 5V, set by ■ Parallel µModule™ DC/DC Converters a single resistor. This high effi ciency design delivers 6A ■ Current Mode Control continuous current (8A peak), needing no heat sinks or ■ Pin Compatible with the LTM4600 and LTM4602 airfl ow to meet power specifi cations. Only bulk input and ■ Up to 92% Effi ciency output capacitors are needed to fi nish the design. ■ Programmable Soft-Start The low profi le package (2.8mm) enables utilization of ■ Output Overvoltage Protection unused space on the bottom of PC boards for high density ■ Optional Short-Circuit Shutdown Timer point of load regulation. High switching frequency and an ■ Pb-Free (e4) RoHS Compliant Package with Gold-Pad adaptive on-time current mode architecture enables a very Finish fast transient response to line and load changes without ■ Small Footprint, Low Profi le (15mm × 15mm × sacrifi cing stability. Fault protection features include 2.8mm) LGA Package integrated overvoltage and short circuit protection with APPLICATIOUS a defeatable shutdown timer. A built-in soft-start timer is adjustable with a small capacitor. ■ Telecom and Networking Equipment The LTM4602HV is packaged in a thermally enhanced, com- ■ Servers pact (15mm × 15mm) and low profi le (2.8mm) over-molded ■ Industrial Equipment Land Grid Array (LGA) package suitable for automated ■ Point of Load Regulation assembly by standard surface mount equipment. For the , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. 4.5V to 20V input range version, refer to the LTM4602. µModule is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents including 5481178, 6100678, 6580258, 5847554, 6304066. TYPICAL APPLICATIOU Effi ciency vs Load Current with 24V (FCB = 0) IN 90 80 6A µModule Power Supply with 4.5V to 28V Input 70 4.5V TO 2V8IVN VIN VOUT V2.O5UVT CY (%) 5600 ABS MAX CIN LTM4602HV COUT 6A CIEN 40 EFFI 30 1.2VOUT VOSET 1.5VOUT PGND SGND 20 1.8VOUT 31.6k 2.5VOUT 10 3.3VOUT 3.3VOUT (1MHz) 4602HV TA01a 0 0 1 2 3 4 5 6 LOAD CURRENT (A) 4602HV G03 4602hvf 1

LTM4602HV ABSOLUTE WAXIWUW RATIUGS PACKAGE/ORDER IUFORWATIOU (Note 1) TOP VIEW FCB, EXTV , PGOOD, RUN/SS, V ..........–0.3V to 6V C VIN, SVIN, fCACDJ ...............................O..U..T.........–0.3V to 28V fADJSVINEXTVCVOSET VOSET, COMP .............................................–0.3V to 2.7V COMP Operating Temperature Range (Note 2) ...–40°C to 85°C VIN SGND RUN/SS Junction Temperature ...........................................125°C FCB Storage Temperature Range ...................–55°C to 125°C PGOOD PGND VOUT LGA PACKAGE 104-LEAD (15mm × 15mm × 2.8mm) TJMAX = 125°C, θJA = 15°C/W, θJC = 6°C/W, θJA DERIVED FROM 95mm × 76mm PCB WITH 4 LAYERS WEIGHT = 1.7g ORDER PART NUMBER LGA PART MARKING* LTM4602HVEV#PBF LTM4602HVV LTM4602HVIV#PBF LTM4602HVV Consult LTC Marketing for parts specifi ed with wider operating temperature ranges. *The temperature grade is identifi ed by a label on the shipping container. ELECTRICAL CHARACTERISTICS The ● denotes the specifi cations which apply over the –40°C to 85°C temperature range, otherwise specifi cations are at T = 25°C, V = 12V. External C = 120µF, C = 200µF/Ceramic per typical A IN IN OUT application (front page) confi guration. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS V Input DC Voltage AbsMax 28V for Tolerance on 24V Inputs ● 4.5 28 V IN(DC) V Output Voltage FCB = 0V OUT(DC) V = 5V or 12V, V = 1.5V, I = 0A 1.478 1.50 1.522 V IN OUT OUT ● 1.470 1.50 1.530 V Input Specifi cations V Under Voltage Lockout Threshold I = 0A 3.4 4 V IN(UVLO) OUT I Input Inrush Current at Startup I = 0A, V = 1.5V, FCB = 0 INRUSH(VIN) OUT OUT V = 5V 0.6 A IN V = 12V 0.7 A IN V = 24V 0.8 A IN I Input Supply Bias Current I = 0A, EXTV Open Q(VIN) OUT CC V = 12V, V = 1.5V, FCB = 5V 1.2 mA IN OUT V = 12V, V = 1.5V, FCB = 0V 42 mA IN OUT V = 24V, V = 2.5V, FCB = 5V 1.8 mA IN OUT V = 24V, V = 2.5V, FCB = 0V 36 mA IN OUT Shutdown, RUN = 0.8V, V = 12V 50 100 µA IN Min On Time 100 ns Min Off Time 400 ns I Input Supply Current V = 12V, V = 1.5V, I = 6A 0.88 A S(VIN) IN OUT OUT V = 12V, V = 3.3V, I = 6A 1.50 A IN OUT OUT V = 5V, V = 1.5V, I = 6A 2.08 A IN OUT OUT V = 24V to 3.3V at 6A, EXTV = 5V 0.98 A IN CC 4602hvf 2

LTM4602HV ELECTRICAL CHARACTERISTICS The ● denotes the specifi cations which apply over the –40°C to 85°C temperature range, otherwise specifi cations are at T = 25°C, V = 12V. Per typical application (front page) confi guration. A IN SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Output Specifi cations I Output Continuous Current Range V = 12V, V = 1.5V 0 6 A OUTDC IN OUT (See Output Current Derating Curves for V = 24V, V = 2.5V (Note 3) 0 6 A IN OUT Different V , V and T ) IN OUT A ΔV Line Regulation Accuracy V = 1.5V. FCB = 0V, I = 0A, ● 0.15 % OUT(LINE) OUT OUT V = 4.5V to 28V V IN OUT ΔV Load Regulation Accuracy V = 1.5V. FCB = 0V, I = 0A to 6A, OUT(0A-6A) OUT OUT V = 5V, V = 12V (Note 4) ±0.25 ±0.5 % V IN IN OUT ● ±0.5 ±1 % V Output Ripple Voltage V = 12V, V = 1.5V, FCB = 0V, I = 0A 10 15 mV OUT(AC) IN OUT OUT P-P fs Output Ripple Voltage Frequency FCB = 0V, I = 6A, V = 12V, 800 kHz OUT IN V = 1.5V OUT t Turn-On Time V = 1.5V, I = 1A START OUT OUT V = 12V 0.5 ms IN V = 5V 0.7 ms IN ΔV Voltage Drop for Dynamic Load Step V = 1.5V, Load Step: 0A/µs to 3A/µs 30 mV OUTLS OUT C = 22µF 6.3V, 330µF 4V Pos Cap, OUT See Table 2 t Settling Time for Dynamic Load Step Load: 10% to 90% to 10% of Full Load 25 µs SETTLE V = 12V IN I Output Current Limit Output Voltage in Foldback OUTPK V = 24V, V = 2.5V 9 A IN OUT V = 12V, V = 1.5V 9 A IN OUT V = 5V, V = 1.5V 9 A IN OUT Control Stage V Voltage at V Pin I = 0A, V = 1.5V ● 0.591 0.6 0.609 V OSET OSET OUT OUT 0.594 0.6 0.606 V V RUN ON/OFF Threshold 0.8 1.5 2 V RUN/SS I Soft-Start Charging Current V = 0V –0.5 –1.2 –3 µA RUN(C)/SS RUN/SS I Soft-Start Discharging Current V = 4V 0.8 1.8 3 µA RUN(D)/SS RUN/SS V – SV EXTV = 0V, FCB = 0V 100 mV IN IN CC I Current into EXTV Pin EXTV = 5V, FCB = 0V, V = 1.5V, 16 mA EXTVCC CC CC OUT I = 0A OUT R Resistor Between V and FB Pins 100 kΩ FBHI OUT V Forced Continuous Threshold 0.57 0.6 0.63 V FCB I Forced Continuous Pin Current V = 0.6V –1 –2 µA FCB FCB PGOOD Output ΔV PGOOD Upper Threshold V Rising 7.5 10 12.5 % OSETH OSET ΔV PGOOD Lower Threshold V Falling –7.5 –10 –12.5 % OSETL OSET ΔV PGOOD Hysteresis V Returning 2 % OSET(HYS) OSET V PGOOD Low Voltage I = 5mA 0.15 0.4 V PGL PGOOD Note 1: Stresses beyond those listed under Absolute Maximum Ratings operating temperature range are assured by design, characterization may cause permanent damage to the device. Exposure to any Absolute and correlation with statistical process controls. The LTM4602HVI is Maximum Rating condition for extended periods may affect device guaranteed and tested over the –40°C to 85°C temperature range. reliability and lifetime. Note 3: Refer to current de-rating curves and thermal application note. Note 2: The LTM4602HVE is guaranteed to meet performance Note 4: Test assumes current derating verses temperature. specifi cations from 0°C to 85°C. Specifi cations over the –40°C to 85°C 4602hvf 3

LTM4602HV TYPICAL PERFORW AU CE CHARACTERISTICS (See Figure 22 for all curves) Effi ciency vs Load Current Effi ciency vs Load Current Effi ciency vs Load Current with 5V (FCB = 0) with 12V (FCB = 0) with 24V (FCB = 0) IN IN IN 100 100 90 90 90 80 80 80 70 70 70 60 %) %) %) CY ( 60 0.8VOUT CY ( 60 CY ( 50 EFFICIEN 345000 1112....2585VVVVOOOOUUUUTTTT EFFICIEN 345000 011...825VVVOOOUUUTTT EFFICIEN 4300 11..25VVOOUUTT 3.3VOUT* 1.8VOUT 20 1.8VOUT 20 *FOR 5V TO 3.3V CONVERSION, 20 2.5VOUT 2.5VOUT 10 SEE FREQUENCY ADJUSTMENT 10 3.3VOUT 10 3.3VOUT IN APPLICATIONS INFORMATION 3.3VOUT (950kHz) 3.3VOUT (1MHz) 0 0 0 0 2 4 6 8 0 2 4 6 8 0 1 2 3 4 5 6 LOAD CURRENT (A) LOAD CURRENT (A) LOAD CURRENT (A) 4602HV G01 4602HV G02 4602HV G03 Light Load Effi ciency vs Load Current with 12V Effi ciency vs Load Current IN (FCB > 0.7V, <5V) with Different FCB Settings 1.2V Transient Response 100 100 VIN = 12V 90 90 VOUT = 1.5V 80 FCB > 0.7V VOUT 80 50mV/DIV 70 Y (%) 60 Y (%) 70 FCB = GND 2AI/ODUIVT C C N 50 N 60 EFFICIE 4300 1.2VOUT EFFICIE 50 1C.O2UVT A=T 2 32Aµ/Fµ,s 6 L.3OVA CD2E0 SRµTAsE/MDPIICV 4602HV G05 1.5VOUT 40 330µF, 4V SANYO POS CAP 20 1.8VOUT 10 2.5VOUT 30 3.3VOUT 0 20 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0.1 1 5 LOAD CURRENT (A) LOAD CURRENT (A) 4602HV G15 4602HV G04 1.5V Transient Response 1.8V Transient Response 2.5V Transient Response VOUT VOUT VOUT 50mV/DIV 50mV/DIV 50mV/DIV IOUT IOUT IOUT 2A/DIV 2A/DIV 2A/DIV 20µs/DIV 4602HV G06 20µs/DIV 4602HV G07 20µs/DIV 4602HV G08 1C3.3O50UVµT AF=,T 42 3V2Aµ S/FµA,s N6 LY.3OOVA PCDOE SSRT ACEMAPPIC 1C3.3O80UVµT AF=,T 42 3V2Aµ S/FµA,s N6 LY.3OOVA PCDOE SSRT ACEMAPPIC 2C3.3O50UVµT AF=,T 42 3V2Aµ S/FµA,s N6 LY.3OOVA PCDOE SSRT ACEMAPPIC 4602hvf 4

LTM4602HV TYPICAL PERFORW AU CE CHARACTERISTICS (See Figure 22 for all curves) Start-Up, I = 6A OUT 3.3V Transient Response Start-Up, IOUT = 0A (Resistive Load) VOUT 50mV/DIV VOUT VOUT 0.5V/DIV 0.5V/DIV IOUT 2A/DIV IIN IIN 0.5A/DIV 20µs/DIV 4602HV G09 0.5A/DIV 3.3V AT 3A/µs LOAD STEP COUT = 22µF, 6.3V CERAMIC VIN = 12V 200µs/DIV 4602HV G10 VIN = 12V 500µs/DIV 4602HV G11 330µF, 4V SANYO POS CAP VOUT = 1.5V VOUT = 1.5V COUT = 1 × 22µF, 6.3V X5R COUT = 1 × 22µF, 6.3V X5R 330µF, 4V SANYO POS CAP 330µF, 4V SANYO POS CAP NO EXTERNAL SOFT-START CAPACITOR NO EXTERNAL SOFT-START CAPACITOR Short-Circuit Protection, Short-Circuit Protection, I = 0A I = 6A V to V Stepdown Ratio OUT OUT IN OUT 5.5 fADJ = OPEN 5V 5.0 VOUT VOUT 4.5 0.5V/DIV 0.5V/DIV 4.0 3.5 3.3V 0.5A/DIIIVN 0.5A/DIIIVN (V)OUT 32..05 2.5V V 2.0 1.8V VIN = 12V 20µs/DIV 4602HV G12 VIN = 12V 20µs/DIV 4602HV G13 1.5 1.5V VOUT = 1.5V VOUT = 1.5V COUT = 1 × 22µF, 6.3V X5R COUT = 1 × 22µF, 6.3V X5R 1.0 1.2V 330µF, 4V SANYO POS CAP 330µF, 4V SANYO POS CAP 0.5 NO EXTERNAL SOFT-START CAPACITOR NO EXTERNAL SOFT-START CAPACITOR 0.6V 0 0 5 10 15 20 25 28 VIN (V) SEE FREQUENCY ADJUSTMENT DISCUSSION FOR 12VIN TO 5VOUT AND 5VIN TO 3.3VOUT CONVERSION 4602HV G14 4602hvf 5

LTM4602HV PIU FUUCTIOUS (See Package Description for Pin Assignment) V (Bank 1): Power Input Pins. Apply input voltage be- SGND (Pin D23): Signal Ground Pin. All small-signal IN tween these pins and PGND pins. Recommend placing components should connect to this ground, which in turn input decoupling capacitance directly between V pins connects to PGND at one point. IN and PGND pins. RUN/SS (Pin F23): Run and Soft-Start Control. Forcing f (Pin A15): A 110k resistor from V to this pin sets this pin below 0.8V will shut down the power supply. ADJ IN the one-shot timer current, thereby setting the switching Inside the power module, there is a 1000pF capacitor frequency. The LTM4602HV switching frequency is typically which provides approximately 0.7ms soft-start time with 850kHz. An external resistor to ground can be selected to 200µF output capacitance. Additional soft-start time can reduce the one-shot timer current, thus lower the switching be achieved by adding additional capacitance between frequency to accommodate a higher duty cycle step down the RUN/SS and SGND pins. The internal short-circuit requirement. See the applications section. latchoff can be disabled by adding a resistor between this pin and the V pin. This resistor must supply a minimum SV (Pin A17): Supply Pin for Internal PWM Controller. Leave IN IN 5µA pull up current. this pin open or add additional decoupling capacitance. FCB (Pin G23): Forced Continuous Input. Grounding this EXTV (Pin A19): External 5V supply pin for controller. If CC pin enables forced continuous mode operation regardless left open or grounded, the internal 5V linear regulator will of load conditions. Tying this pin above 0.63V enables power the controller and MOSFET drivers. For high input discontinuous conduction mode to achieve high effi ciency voltage applications, connecting this pin to an external operation at light loads. There is an internal 10k resistor 5V will reduce the power loss in the power module. The between the FCB and SGND pins. EXTV voltage should never be higher than V . CC IN PGOOD (Pin J23): Output Voltage Power Good Indicator. V (Pin A21): The Negative Input of The Error Amplifi er. OSET When the output voltage is within 10% of the nominal Internally, this pin is connected to V with a 100k precision OUT voltage, the PGOOD is open drain output. Otherwise, this resistor. Different output voltages can be programmed with pin is pulled to ground. additional resistors between the V and SGND pins. OSET PGND (Bank 2): Power ground pins for both input and COMP (Pin B23): Current Control Threshold and Error output returns. Amplifi er Compensation Point. The current comparator threshold increases with this control voltage. The voltage V (Bank 3): Power Output Pins. Apply output load OUT ranges from 0V to 2.4V with 0.8V corresponding to zero between these pins and PGND pins. Recommend placing sense voltage (zero current). High Frequency output decoupling capacitance directly between these pins and PGND pins. TOP VIEW fADJ SVIN EXTVCC VOSET 2 3 4 5 6 7 16 17 18 19 A 1 20 B COMP BANVKI N1 8 9 10 11 21 CD SGND 13 14 15 E 12 22 F RUN/SS 25 23 G FCB 26 27 28 29 30 31 H 32 24 J PGOOD 33 34 35 36 37 38 K PGND 39 40 41 42 43 44 45 46 47 48 49 L BANK 2 50 51 52 53 54 55 56 57 58 59 60 M 61 62 63 64 65 66 67 68 69 70 71 N 72 73 74 75 76 77 78 79 80 81 82 P BAVNOKU 3T 83 84 85 86 87 88 89 90 91 92 93 R 94 95 96 97 98 99 100 101 102 103 104 T 1 3 5 7 9 11 13 15 17 19 21 23 2 4 6 8 10 12 14 16 18 20 22 4600hv PN01 4602hvf 6

LTM4602HV SI W PLIFIED BLOCK DIAGRAW SVIN RUN/SS 1000pF VIN 4.5V TO 28V ABS MAX PGOOD 1.5µF CIN Q1 COMP INT COMP VOUT 2.5V FCB 6A MAX VIN COUT 4.75k 15µF CONTROLLER 110k 6.3V fADJ SGND 10Ω Q2 PGND EXTVCC 100k 0.5% VOSET RSET 31.6k 4602HV F01 Figure 1. Simplifi ed LTM4602HV Block Diagram DECOUPLI U G REQUIREW E U TS T = 25°C, V = 12V. Use Figure 1 confi guration. A IN SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS C External Input Capacitor Requirement I = 6A, 2x 10µF 35V Ceramic 20 µF IN OUT (V = 4.5V to 28V, V = 2.5V) Taiyo Yuden GDK316BJ106ML IN OUT C External Output Capacitor Requirement I = 6A, Refer to Table 2 in the 100 200 µF OUT OUT (V = 4.5V to 28V, V = 2.5V) Applications Information Section IN OUT 4602hvf 7

LTM4602HV OPERATIOU µModule Description in an overvoltage condition, internal top FET Q1 is turned off and bottom FET Q2 is turned on and held on until the The LTM4602HV is a standalone non-isolated synchronous overvoltage condition clears. switching DC/DC power supply. It can deliver up to 6A of DC output current with only bulk external input and output Pulling the RUN/SS pin low forces the controller into its capacitors. This module provides a precisely regulated shutdown state, turning off both Q1 and Q2. Releasing the output voltage programmable via one external resistor from pin allows an internal 1.2µA current source to charge up 0.6V to 5.0V . The input voltage range is 4.5V to 28V. the softstart capacitor. When this voltage reaches 1.5V, DC DC A simplifi ed block diagram is shown in Figure 1 and the the controller turns on and begins switching. typical application schematic is shown in Figure 21. At low load current the module works in continuous cur- The LTM4602HV contains an integrated LTC constant rent mode by default to achieve minimum output voltage on-time current-mode regulator, ultra-low R FETs ripple. It can be programmed to operate in discontinuous DS(ON) with fast switching speed and integrated Schottky diode. current mode for improved light load effi ciency when the The typical switching frequency is 800kHz at full load. FCB pin is pulled up above 0.8V and no higher than 6V. With current mode control and internal feedback loop The FCB pin has a 10k resistor to ground, so a resistor to compensation, the LTM4602HV module has suffi cient V can set the voltage on the FCB pin. IN stability margins and good transient performance under a When EXTV pin is grounded or open, an integrated 5V CC wide range of operating conditions and with a wide range linear regulator powers the controller and MOSFET gate of output capacitors, even all ceramic output capacitors drivers. If a minimum 4.7V external bias supply is ap- (X5R or X7R). plied on the EXTV pin, the internal regulator is turned CC Current mode control provides cycle-by-cycle fast current off, and an internal switch connects EXTV to the gate CC limit. In addition, foldback current limiting is provided driver voltage. This eliminates the linear regulator power in an over-current condition while V drops. Also, the loss with high input voltage, reducing the thermal stress FB LTM4602HV has defeatable short circuit latch off. Internal on the controller. The maximum voltage on EXTV pin is CC overvoltage and undervoltage comparators pull the open- 6V. The EXTV voltage should never be higher than the CC drain PGOOD output low if the output feedback voltage exits V voltage. Also EXTV must be sequenced after V . IN CC IN a ±10% window around the regulation point. Furthermore, Recommended for 24V operation to lower temperature in the µModule. 4602hvf 8

LTM4602HV APPLICATIOUS IUFORWATIOU The typical LTM4602HV application circuit is shown in voltage is margined up. The output voltage is margined Figure 20. External component selection is primarily down when Q is on and Q is off. If the output DOWN UP determined by the maximum load current and output voltage V needs to be margined up/down by ±M%, the O voltage. resistor values of R and R can be calculated from UP DOWN the following equations: Output Voltage Programming and Margining (R R )(cid:127)V (cid:127)(1+M%) The PWM controller of the LTM4602HV has an internal SET UP O =0.6V (R R )+100kΩ 0.6V±1% reference voltage. As shown in the block diagram, SET UP a 100k/0.5% internal feedback resistor connects V and OUT R (cid:127)V (cid:127)(1–M%) FB pins. Adding a resistor RSET from VOSET pin to SGND SET O =0.6V pin programs the output voltage: RSET +(100kΩRDOWN) 100k+R VO =0.6V(cid:127) SET Input Capacitors R SET The LTM4602HV µModule should be connected to a low Table 1 shows the standard values of 1% RSET resistor ac-impedance DC source. High frequency, low ESR input for typical output voltages: capacitors are required to be placed adjacent to the mod- Table 1 ule. In Figure 20, the bulk input capacitor CIN is selected for its ability to handle the large RMS current into the R (kSΩET) Open 100 66.5 49.9 43.2 31.6 22.1 13.7 converter. For a buck converter, the switching duty-cycle V can be estimated as: O 0.6 1.2 1.5 1.8 2 2.5 3.3 5 (V) V Voltage margining is the dynamic adjustment of the output D = O V voltage to its worst case operating range in production IN testing to stress the load circuitry, verify control/protec- Without considering the inductor current ripple, the RMS tion functionality of the board and improve the system current of the input capacitor can be estimated as: reliability. Figure 2 shows how to implement margining function with the LTM4602HV. In addition to the feedback I I = O(MAX) (cid:127) D(cid:127)(1−D) resistor RSET, several external components are added. CIN(RMS) η% Turn off both transistor Q and Q to disable the UP DOWN margining. When Q is on and Q is off, the output In the above equation, η% is the estimated effi ciency of UP DOWN the power module. C1 can be a switcher-rated electrolytic aluminum capacitor, OS-CON capacitor or high volume VOUT LTM4602HV ceramic capacitors. Note the capacitor ripple current RDOWN ratings are often based on only 2000 hours of life. This 100k makes it advisable to properly derate the input capacitor, QDOWN or choose a capacitor rated at a higher temperature than VOSET 2N7002 required. Always contact the capacitor manufacturer for PGND SGND derating requirements. RSET RUP In Figure 16, the input capacitors are used as high frequency QUP input decoupling capacitors. In a typical 6A output applica- 2N7002 tion, 1-2 pieces of very low ESR X5R or X7R, 10µF ceramic 4602HV F02 capacitors are recommended. This decoupling capacitor Figure 2 should be placed directly adjacent the module input pins 4602hvf 9

LTM4602HV APPLICATIOUS IUFORWATIOU in the PCB layout to minimize the trace inductance and Soft-Start and Latchoff with the RUN/SS pin high frequency AC noise. The RUN/SS pin provides a means to shut down the LTM4602HV as well as a timer for soft-start and over- Output Capacitors current latchoff. Pulling the RUN/SS pin below 0.8V puts The LTM4602HV is designed for low output voltage ripple. the LTM4602HV into a low quiescent current shutdown The bulk output capacitor COUT is chosen with low enough (IQ ≤ 75µA). Releasing the pin allows an internal 1.2µA effective series resistance (ESR) to meet the output voltage current source to charge up the timing capacitor C . SS ripple and transient requirements. COUT can be low ESR Inside LTM4602HV, there is an internal 1000pF capaci- tantalum capacitor, low ESR polymer capacitor or ceramic tor from RUN/SS pin to ground. If RUN/SS pin has an capacitor (X5R or X7R). The typical capacitance is 200µF external capacitor C to ground, the delay before SS_EXT if all ceramic output capacitors are used. The internally starting is about: optimized loop compensation provides suffi cient stability 1.5V margin for all ceramic capacitors applications. Additional t = (cid:127)(C +1000pF) output fi ltering may be required by the system designer, DELAY 1.2µA SS_EXT if further reduction of output ripple or dynamic transient When the voltage on RUN/SS pin reaches 1.5V, the spike is required. Refer to Table 2 for an output capaci- LTM4602HV internal switches are operating with a clamp- tance matrix for each output voltage Droop, peak to peak ing of the maximum output inductor current limited by the deviation and recovery time during a 3A/µs transient with RUN/SS pin total soft-start capacitance. As the RUN/SS pin a specifi c output capacitance. voltage rises to 3V, the soft-start clamping of the inductor current is released. Fault Conditions: Current Limit and Over current Foldback V to V Stepdown Ratios IN OUT The LTM4602HV has a current mode controller, which There are restrictions in the maximum V to V step inherently limits the cycle-by-cycle inductor current not IN OUT down ratio that can be achieved for a given input voltage. only in steady state operation, but also in transient. These constraints are shown in the Typical Performance To further limit current in the event of an over load condi- Characteristics curves labeled “V to V Stepdown IN OUT tion, the LTM4602HV provides foldback current limiting. Ratio”. Note that additional thermal de-rating may apply. If the output voltage falls by more than 50%, then the See the Thermal Considerations and Output Current De- maximum output current is progressively lowered to about Rating sections of this data sheet. one sixth of its full current limit value. 4602hvf 10

LTM4602HV APPLICATIOUS IUFORWATIOU Table 2. Output Voltage Response Versus Component Matrix (Refer to Figure 17), 0A to 3A Step (Typical Values) TYPICAL MEASURED VALUES COUT1 VENDORS PART NUMBER COUT2 VENDORS PART NUMBER TDK C4532X5R0J107MZ (100UF,6.3V) SANYO POS CAP 6TPE330MIL (330µF, 6.3V) TAIYO YUDEN JMK432BJ107MU-T ( 100µF, 6.3V) SANYO POS CAP 2R5TPE470M9 (470µF, 2.5V) TAIYO YUDEN JMK316BJ226ML-T501 ( 22µF, 6.3V) SANYO POS CAP 4TPE470MCL (470µF, 4V) VOUT CIN CIN COUT1 COUT2 CCOMP C3 VIN DROOP PEAK TO PEAK RECOVERY TIME LOAD STEP (V) (CERAMIC) (BULK) (CERAMIC) (BULK) (V) (mV) (mV) (µs) (A/µs) 1.2 2 × 10µF 25V 150µF 35V 3 × 22µF 6.3V 470µF 4V NONE 100pF 5 30 60 25 3 1.2 2 × 10µF 25V 150µF 35V 1 × 100µF 6.3V 470µF 2.5V NONE 100pF 5 30 60 20 3 1.2 2 × 10µF 25V 150µF 35V 2 × 100µF 6.3V 330µF 6.3V NONE 100pF 5 25 54 20 3 1.2 2 × 10µF 25V 150µF 35V 4 × 100µF 6.3V NONE NONE 100pF 5 25 55 20 3 1.2 2 × 10µF 25V 150µF 35V 3 × 22µF 6.3V 470µF 4V NONE 100pF 12 30 60 25 3 1.2 2 × 10µF 25V 150µF 35V 1 × 100µF 6.3V 470µF 2.5V NONE 100pF 12 25 54 20 3 1.2 2 × 10µF 25V 150µF 35V 2 × 100µF 6.3V 330µF 6.3V NONE 100pF 12 25 56 20 3 1.2 2 × 10µF 25V 150µF 35V 4 × 100µF 6.3V NONE NONE 100pF 12 25 55 20 3 1.5 2 × 10µF 25V 150µF 35V 3 × 22µF 6.3V 470µF 4V NONE 100pF 5 25 50 25 3 1.5 2 × 10µF 25V 150µF 35V 1 × 100µF 6.3V 470µF 2.5V NONE 100pF 5 25 54 20 3 1.5 2 × 10µF 25V 150µF 35V 2 × 100µF 6.3V 330µF 6.3V NONE 100pF 5 25 59 20 3 1.5 2 × 10µF 25V 150µF 35V 4 × 100µF 6.3V NONE NONE 100pF 5 26 59 20 3 1.5 2 × 10µF 25V 150µF 35V 3 × 22µF 6.3V 470µF 4V NONE 100pF 12 25 55 25 3 1.5 2 × 10µF 25V 150µF 35V 1 × 100µF 6.3V 470µF 2.5V NONE 100pF 12 25 54 20 3 1.5 2 × 10µF 25V 150µF 35V 2 × 100µF 6.3V 330µF 6.3V NONE 100pF 12 28 59 20 3 1.5 2 × 10µF 25V 150µF 35V 4 × 100µF 6.3V NONE NONE 100pF 12 26 59 20 3 1.8 2 × 10µF 25V 150µF 35V 3 × 22µF 6.3V 470µF 4V NONE 100pF 5 25 54 30 3 1.8 2 × 10µF 25V 150µF 35V 1 × 100µF 6.3V 470µF 2.5V NONE 100pF 5 25 50 20 3 1.8 2 × 10µF 25V 150µF 35V 2 × 100µF 6.3V 330µF 6.3V NONE 100pF 5 25 50 20 3 1.8 2 × 10µF 25V 150µF 35V 4 × 100µF 6.3V NONE NONE 100pF 5 29 60 20 3 1.8 2 × 10µF 25V 150µF 35V 3 × 22µF 6.3V 470µF 4V NONE 100pF 12 25 50 30 3 1.8 2 × 10µF 25V 150µF 35V 1 × 100µF 6.3V 470µF 2.5V NONE 100pF 12 25 50 20 3 1.8 2 × 10µF 25V 150µF 35V 2 × 100µF 6.3V 330µF 6.3V NONE 100pF 12 25 50 20 3 1.8 2 × 10µF 25V 150µF 35V 4 × 100µF 6.3V NONE NONE 100pF 12 29 60 20 3 2.5 2 × 10µF 25V 150µF 35V 1 × 100µF 6.3V 470µF 4V NONE 220pF 5 25 50 30 3 2.5 2 × 10µF 25V 150µF 35V 2 × 100µF 6.3V 330µF 6.3V NONE 220pF 5 25 50 30 3 2.5 2 × 10µF 25V 150µF 35V 3 × 22µF 6.3V 470µF 4V NONE 220pF 5 25 50 30 3 2.5 2 × 10µF 25V 150µF 35V 4 × 100µF 6.3V NONE NONE 220pF 5 25 50 25 3 2.5 2 × 10µF 25V 150µF 35V 1 × 100µF 6.3V 470µF 4V NONE 220pF 12 25 50 30 3 2.5 2 × 10µF 25V 150µF 35V 3 × 22µF 6.3V 470µF 4V NONE 220pF 12 25 50 30 3 2.5 2 × 10µF 25V 150µF 35V 2 × 100µF 6.3V 330µF 6.3V NONE 220pF 12 25 50 30 3 2.5 2 × 10µF 25V 150µF 35V 4 × 100µF 6.3V NONE NONE 220pF 12 27 54 25 3 3.3 2 × 10µF 25V 150µF 35V 2 × 100µF 6.3V 330µF 6.3V NONE 220pF 7 32 64 30 3 3.3 2 × 10µF 25V 150µF 35V 1 × 100µF 6.3V 470µF 4V NONE 220pF 7 30 60 30 3 3.3 2 × 10µF 25V 150µF 35V 3 × 22µF 6.3V 470µF 4V NONE 220pF 7 30 60 35 3 3.3 2 × 10µF 25V 150µF 35V 4 × 100µF 6.3V NONE NONE 220pF 7 32 64 25 3 3.3 2 × 10µF 25V 150µF 35V 1 × 100µF 6.3V 470µF 4V NONE 220pF 12 38 58 30 3 3.3 2 × 10µF 25V 150µF 35V 3 × 22µF 6.3V 470µF 4V NONE 220pF 12 30 60 35 3 3.3 2 × 10µF 25V 150µF 35V 2 × 100µF 6.3V 330µF 6.3V NONE 220pF 12 30 60 30 3 3.3 2 × 10µF 25V 150µF 35V 4 × 100µF 6.3V NONE NONE 220pF 12 32 64 25 3 5 1 × 10µF 25V 150µF 35V 4 × 100µF 6.3V NONE NONE 100pF 15 80 160 25 3 5 1 × 10µF 25V 150µF 35V 4 × 100µF 6.3V NONE NONE 100pF 20 80 160 25 3 4602hvf 11

LTM4602HV APPLICATIOUS IUFORWATIOU After the controller has been started and given adequate 4V maximum latchoff threshold and overcome the 4µA time to charge up the output capacitor, C is used as a maximum discharge current. Figure 3 shows a conceptual SS short-circuit timer. After the RUN/SS pin charges above 4V, drawing of V during startup and short circuit. RUN if the output voltage falls below 75% of its regulated value, then a short-circuit fault is assumed. A 1.8µA current then VRUN/SS begins discharging C . If the fault condition persists until SS 4V the RUN/SS pin drops to 3.5V, then the controller turns 3.5V 3V off both power MOSFETs, shutting down the converter permanently. The RUN/SS pin must be actively pulled 1.5V SHORT-CIRCUIT down to ground in order to restart operation. LATCH ARMED The over-current protection timer requires the soft-start t SOFT-START OUTPUT SHORT-CIRCUIT timing capacitor CSS be made large enough to guarantee CLAMPING OVERLOAD LATCHOFF that the output is in regulation by the time C has reached OF IL RELEASED HAPPENS SS the 4V threshold. In general, this will depend upon the size VO of the output capacitance, output voltage and load current 75%VO characteristic. A minimum external soft-start capacitor can be estimated from: SWITCHING t STARTS 4602HV F03 C +1000pF >C (cid:127)V (10–3[F/V ]) SS_EXT OUT OUT S Figure 3. RUN/SS Pin Voltage During Startup and Short-Circuit Protection Generally 0.1µF is more than suffi cient. Since the load current is already limited by the current mode VIN VIN control and current foldback circuitry during a short circuit, 500k LTM4602HV overcurrent latchoff operation is NOT always needed or RUN/SS desired, especially if the output has large capacitance or PGND SGND the load draws high current during start-up. The latchoff feature can be overridden by a pull-up current greater than RECOMMENDED VALUES FOR RRUN/SS 5µA but less than 80µA to the RUN/SS pin. The additional VIN RRUN/SS current prevents the discharge of C during a fault and SS 4.5V TO 5.5V 50k also shortens the soft-start period. Using a resistor from 10.8V TO 13.8V 150k 24V TO 28V 500k RUN/SS pin to V is a simple solution to defeat latchoff. Any 4602HV F04 IN pull-up network must be able to maintain RUN/SS above Figure 4. Defeat Short-Circuit Latchoff with a Pull-Up Resistor to V IN 4602hvf 12

LTM4602HV APPLICATIOUS IUFORWATIOU Enable EXTV Connection CC The RUN/SS pin can be driven from logic as shown in An internal low dropout regulator produces an internal 5V Figure 5. This function allows the LTM4602HV to be supply that powers the control circuitry and FET drivers. turned on or off remotely. The ON signal can also control Therefore, if the system does not have a 5V power rail, the sequence of the output voltage. the LTM4602HV can be directly powered by V . The gate IN driver current through LDO is about 16mA. The internal LDO power dissipation can be calculated as: RUN/SS P = 16mA • (V – 5V) ON LTM4602HV LDO_LOSS IN The LTM4602HV also provides an external gate driver PGND SGND voltage pin EXTV . If there is a 5V rail in the system, it CC 2N7002 is recommended to connect EXTV pin to the external 4602HV F05 CC 5V rail. Whenever the EXTV pin is above 4.7V, the in- CC Figure 5. Enable Circuit with External Logic ternal 5V LDO is shut off and an internal 50mA P-channel Output Voltage Tracking switch connects the EXTV to internal 5V. Internal 5V is CC supplied from EXTV until this pin drops below 4.5V. Do For the applications that require output voltage tracking, CC not apply more than 6V to the EXTV pin and ensure that several LTM4602HV modules can be programmed by the CC EXTV < V . The following list summaries the possible power supply tracking controller such as the LTC2923. CC IN connections for EXTV : Figure 6 shows a typical schematic with LTC2923. Coin- CC cident, ratiometric and offset tracking for V rising and 1. EXTV grounded. Internal 5V LDO is always powered O CC falling can be implemented with different sets of resistor from the internal 5V regulator. values. See the LTC2923 data sheet for more details. 2. EXTV connected to an external supply. Internal LDO CC VIN DC/DC Q1 3.3V is shut off. A high effi ciency supply compatible with the 5V MOSFET gate drive requirements (typically 5V) can im- prove overall effi ciency. With this connection, it is always VIN required that the EXTV voltage can not be higher than CC VIN V pin voltage. IN RONB VCC GATE RAMP LTM4602HV ON FB1 VOSET VOUT 1.8V RONA RSET Discontinuous Operation and FCB Pin LTC2923 49.9k The FCB pin determines whether the internal bottom RAMPBUF STATUS RTB1 VIN MOSFET remains on when the inductor current reverses. There is an internal 10k pulling down resistor connecting TRACK1 SDO VIN RTA1 RTB2 LTM4602HV this pin to ground. The default light load operation mode TRACK2 FB2 VOSET VOUT 1.5V is forced continuous (PWM) current mode. This mode RTA2 GND R66S.E5Tk provides minimum output voltage ripple. 4602HV F06 Figure 6. Output Voltage Tracking with the LTC2923 Controller 4602hvf 13

LTM4602HV APPLICATIOUS IUFORWATIOU In the application where the light load effi ciency is im- approximate θ for the module with various heatsink- JA portant, tying the FCB pin above 0.6V threshold enables ing methods. Thermal models are derived from several discontinuous operation where the bottom MOSFET turns temperature measurements at the bench, and thermal off when inductor current reverses. Therefore, the conduc- modeling analysis. Application Note 103 provides a detailed tion loss is minimized and light load effi cient is improved. explanation of the analysis for the thermal models, and the The penalty is that the controller may skip cycle and the derating curves. Tables 3 and 4 provide a summary of the output voltage ripple increases at light load. equivalent θ for the noted conditions. These equivalent JA θ parameters are correlated to the measure values, and JA Paralleling Operation with Load Sharing improved with air-fl ow. The case temperature is maintained at 100°C or below for the derating curves. This allows for Two or more LTM4602HV modules can be paralleled to 4W maximum power dissipation in the total module with provide higher than 6A output current. Figure 7 shows top and bottom heatsinking, and 2W power dissipation the necessary interconnection between two paralleled through the top of the module with an approximate θ modules. The OPTI-LOOP™ current mode control en- JC between 6°C/W to 9°C/W. This equates to a total of 124°C sures good current sharing among modules to balance at the junction of the device. The θ values in Tables 3 the thermal stress. The new feedback equation for two or JA and 4 can be used to derive the derating curves for other more LTM4602HVs in parallel is: output voltages. 100k +R SET Safety Considerations V =0.6V(cid:127) N OUT R SET The LTM4602HV modules do not provide isolation from V to V . There is no internal fuse. If required, a slow where N is the number of LTM4602HVs in parallel. IN OUT blow fuse with a rating twice the maximum input current Thermal Considerations and Output Current Derating should be provided to protect each unit from catastrophic failure. The power loss curves in Figures 8 and 15 can be used in coordination with the load current derating curves in OPTI-LOOP is a trademark of Linear Technology Corporation. Figures 9 to 14, and Figures 16 to 19 for calculating an VPULLUP 100k PGOOD VIN VIN LTM4602HV VOUT V12OAU TMAX PGND COMP VOSET SGND RSET PGOODCOMP VOSET SGND VIN LTM4602HV VOUT PGND 4602HV F07 Figure 7. Parallel Two µModules with Load Sharing 4602hvf 14

LTM4602HV APPLICATIOUS IUFORWATIOU 2.0 7 7 1.8 6 6 1.6 1.4 5 5 R LOSS (W) 11..20 12V TOL 1O.S5VS RENT (A) 4 RENT (A) 4 WE 0.8 UR 3 UR 3 O C C P 0.6 5V TO 1.5V 2 2 LOSS 0.4 1 0LFM 1 0LFM 0.2 200LFM 200LFM 400LFM 400LFM 0 0 0 0.6 1.0 2.1 3.1 4.1 5.1 6.1 50 60 70 80 90 100 50 60 70 80 90 100 CURRENT (A) TEMPERATURE (°C) TEMPERATURE (°C) 4602HV F08 4602HV F09 4602HV F10 Figure 8. 1.5V Power Loss Curves Figure 9. 5V to 1.5V, No Heatsink Figure 10. 5V to 1.5V, BGA Heatsink vs Load Current 7 7 4.0 5V TO 3.3V LOSS 6 6 3.5 1122VV TTOO 33..33VV L(9O5S0SkHz) LOSS 3.0 5 5 W) CURRENT (A) 43 CURRENT (A) 43 OWER LOSS ( 212...055 P 2 2 1.0 1 02L0F0MLFM 1 02L0F0MLFM 0.5 400LFM 400LFM 0 0 0 50 60 70 80 90 100 50 60 70 80 90 100 0.5 1.0 2.1 3.1 4.1 5.1 6.1 TEMPERATURE (°C) TEMPERATURE (°C) CURRENT (A) 4602HV F11 4602HV F09 4602HV F13 Figure 11. 12V to 1.5V, No Heatsink Figure 12. 12V to 1.5V, BGA Heatsink Figure 13. 3.3V Power Loss 7 7 7 6 6 6 5 5 5 A) A) A) T ( 4 T ( 4 T ( 4 N N N E E E R R R R 3 R 3 R 3 U U U C C C 2 2 2 0LFM 0LFM 0LFM 1 1 1 200LFM 200LFM 200LFM 400LFM 400LFM 400LFM 0 0 0 50 60 70 80 90 100 50 60 70 80 90 100 50 60 70 80 90 100 TEMPERATURE (°C) TEMPERATURE (°C) TEMPERATURE (°C) 4602HV F14 4602HV F15 4602HV F16 Figure 14. 5V to 3.3V, No Heatsink Figure 15. 5V to 3.3V, BGA Heatsink Figure 16. 12V to 3.3V (950kHz), No Heatsink 4602hvf 15

LTM4602HV APPLICATIOUS IUFORWATIOU 7 7 7 6 6 6 5 5 5 A) A) A) NT ( 4 NT ( 4 NT ( 4 RE RE RE R 3 R 3 R 3 U U U C C C 2 2 2 1 0LFM 1 0LFM 1 0LFM 200LFM 200LFM 200LFM 400LFM 400LFM 400LFM 0 0 0 50 60 70 80 90 100 50 60 70 80 90 100 50 60 70 80 90 100 TEMPERATURE (°C) TEMPERATURE (°C) TEMPERATURE (°C) 4602HV F16 4602HV F18 4602HV F19 Figure 17. 12V to 3.3V (950kHz), Figure 18. 24V to 3.3V, No Heatsink Figure 19. 24V to 3.3V, BGA Heatsink BGA Heatsink Table 3. 1.5V Output Table 4. 3.3V Output AIR FLOW (LFM) HEATSINK θ (°C/W) AIR FLOW (LFM) HEATSINK θ (°C/W) JA JA 0 None 15.2 0 None 15.2 200 None 14 200 None 14.6 400 None 12 400 None 13.4 0 BGA Heatsink 13.9 0 BGA Heatsink 13.9 200 BGA Heatsink 11.3 200 BGA Heatsink 11.1 400 BGA Heatsink 10.25 400 BGA Heatsink 10.5 Layout Checklist/Example • Do not put via directly on pad The high integration of the LTM4602HV makes the PCB • Use a separated SGND ground copper area for com- board layout very simple and easy. However, to optimize ponents connected to signal pins. Connect the SGND its electrical and thermal performance, some layout con- to PGND underneath the unit siderations are still necessary. Figure 20 gives a good example of the recommended • Use large PCB copper areas for high current path, in- layout. cluding V , PGND and V . It helps to minimize the IN OUT PCB conduction loss and thermal stress LTM4602 Frequency Adjustment • Place high frequency ceramic input and output capaci- The LTM4602HV is designed to typically operate at 850kHz tors next to the V , PGND and V pins to minimize across most input and output conditions. The control ar- IN OUT high frequency noise chitecture is constant on time valley mode current control. The f pin is typically left open or decoupled with an ADJ • Place a dedicated power ground layer underneath optional 1000pF capacitor. The switching frequency has the unit been optimized to maintain constant output ripple over the • To minimize the via conduction loss and reduce module operating conditions. The equations for setting the operat- thermal stress, use multiple vias for interconnection ing frequency are set around a programmable constant between top layer and other power layers on time. This on time is developed by a programmable 4602hvf 16

LTM4602HV APPLICATIOUS IUFORWATIOU VIN The LTM4602 has a minimum (tON) on time of 100 nanosec- onds and a minimum (t ) off time of 400 nanoseconds. OFF The 2.4V clamp on the ramp threshold as a function of V will cause the switching frequency to increase by the OUT CIN ratio of V /2.4V for 3.3V and 5V outputs. This is due to OUT the fact the on time will not increase as V increases OUT past 2.4V. Therefore, if the nominal switching frequency is 850kHz, then the switching frequency will increase to ~1.2MHz for 3.3V, and ~1.7MHz for 5V outputs due PGND to Frequency = (DC/t ) When the switching frequency ON increases to 1.2MHz, then the time period ts is reduced to ~833 nanoseconds and at 1.7MHz the switching period VOUT 4602HV F20 reduces to ~588 nanoseconds. When higher duty cycle LOAD conversions like 5V to 3.3V and 12V to 5V need to be TOP LAYER accommodated, then the switching frequency can be lowered to alleviate the violation of the 400ns minimum Figure 20. Recommended PCB Layout off time. Since the total switching period is t = t + t , ON OFF current into an on board 10pF capacitor that establishes tOFF will be below the 400ns minimum off time. A resistor a ramp that is compared to a voltage threshold that is from the fADJ pin to ground can shunt current away from equal to the output voltage up to a 2.4V clamp. This I the on time generator, thus allowing for a longer on time ON current is equal to: I = (V – 0.7V)/110k, with the 110k and a lower switching frequency. 12V to 5V and 5V to ON IN onboard resistor from V to f . The on time is equal to 3.3V derivations are explained in the data sheet to lower IN ADJ t = (V /I ) • 10pF and t = t – t . The frequency switching frequency and accommodate these step-down ON OUT ON OFF s ON is equal to: Freq. = DC/t . The I current is proportional conversions. ON ON to V , and the regulator duty cycle is inversely propor- IN Equations for setting frequency: V = 5V OUT tional to V , therefore the step-down regulator will remain IN I = (V – 0.7V)/110k; for 12V input, I = 103µA relatively constant frequency as the duty cycle adjustment ON IN ON takes place with lowering VIN. The on time is proportional frequency = (ION/[2.4V • 10pF]) • (DC) = 1.79MHz; to VOUT up to a 2.4V clamp. This will hold frequency rela- DC = duty cycle, duty cycle is (VOUT/VIN) tively constant with different output voltages up to 2.4V. t = t + t , t = on-time, t = off-time of the The regulator switching period is comprised of the on ON OFF ON OFF switching period; t = 1/frequency time and off time as depicted in Figure 21. The on time is equal to t = (V /I ) • 10pF and t = t – t . The t must be greater than 400ns, or t – t > 400ns. ON OUT ON OFF s ON OFF ON frequency is equal to: Frequency = DC/t ). ON t = DC • t ON 1MHz frequency or 1µs period is chosen. (DC) DUTY CYCLE = tON ts DC = tON= VOUT tON = 0.41 • 1µs ≅ 410ns ts VIN DC t = 1µs – 410ns ≅ 590ns FREQ = OFF tOFF tON tON t and t are above the minimums with adequate guard ON OFF 4602HV F21 band. PERIOD ts Figure 21 4602hvf 17

LTM4602HV APPLICATIOUS IUFORWATIOU Using the frequency = (I /[2.4V • 10pF]) • (DC), solve for Using the frequency = (I /[2.4V • 10pF]) • (DC), solve ON ON I = (1MHz • 2.4V • 10pF) • (1/0.41) ≅ 58µA. I current for I = (450kHz • 2.4V • 10pF) • (1/0.66) ≅ 16µA. I ON ON ON ON calculated from 12V input was 103µA, so a resistor from current calculated from 5V input was 39µA, so a resistor f to ground = (0.7V/15k) = 46µA. 103µA – 46µA = from f to ground = (0.7V/30.1k) = 23µA. 39µA – 23µA ADJ ADJ 57µA, sets the adequate I current for proper frequency = 16µA, sets the adequate I current for proper frequency ON ON range for the higher duty cycle conversion of 12V to range for the higher duty cycle conversion of 5V to 3.3V. 5V. Input voltage range is limited to 8V to 16V. Higher Input voltage range is limited to 4.5V to 7V. Higher input input voltages can be used without the 15k on f . voltages can be used without the 30.1k on f . The induc- ADJ ADJ The inductor ripple current gets too high above 16V or tor ripple current gets too high above 7V, and the 400ns below 8V. minimum off-time is limited below 4.5V. Equations for setting frequency: V = 3.3V Therefore, at 3.3V output, a 30.1k resistor is recommended OUT to add from pin f to ground when the input voltage is I = (V – 0.7V)/110k; for 5V input, I = 39µA ADJ ON IN ON between 4.5V to 7V. However, this resistor needs to be frequency = (ION/[2.4V • 10pF]) • (DC) = 1.07MHz; removed to avoid high inductor ripple current when the DC = duty cycle, duty cycle is (VOUT/VIN) input voltage is more than 7V. Similarly, for 5V output, a 15k resistor is recommended to adjust the frequency when t = t + t , t = on-time, t = off-time of the ON OFF ON OFF the input voltage is between 8V to 16V. This 15k resistor switching period; t = 1/frequency is removed when the input voltage becomes higher than t must be greater than 400ns, or t – t > 400ns. OFF ON 16V. Please refer to the Typical Performance curve V to IN tON = DC • t VOUT Step-Down Ratio. ~450kHz frequency or 2.22µs period is chosen. Frequency In 12V to 3.3V and 24V to 3.3V applications, if a 35k range is about 450kHz to 650kHz from 4.5V to 7V input. resistor is added from the fADJ pin to ground, then a 2% effi ciency gain will be achieved as shown in the 12V and t = 0.66 • 2.22µs ≅ 1.46µs ON 24V effi ciency graphs shown in the Typical Characteris- t = 2.22µs – 1.46µs ≅ 760ns tics. This is due to lowering the transition losses in the OFF power MOSFETs by reducing the switching frequency t and t are above the minimums with adequate guard ON OFF from 1.3mHz to 1mHz. band. 5V to 3.3V at 5A VIN R1 4.5V TO 7V 30.1k C3 C1 C5 10µF 10µF VIN fADJ 100pF VOUT 25V 25V 3.3V AT 5A EFFICIENCY = 92% EXTVCC VOUT + C4 FCB LTM4602HV VOSET RSET C222µF 363.30VµF 22.1k RUN/SOFT-START RUN/SS SVIN 1% COMP PGOOD OPEN DRAIN SGND PGND 4602HV F23 5V TO 3.3V AT 5A WITH fADJ = 30.1k C1, C3: TDK C3216X5R1E106MT LTM4602HV MINIMUM ON-TIME = 100ns C2: TAIYO YUDEN, JMK316BJ226ML LTM4602HV MINIMUM OFF-TIME = 400ns C4: SANYO POS CAP, 6TPE330MIL 4602hvf 18

LTM4602HV APPLICATIOUS IUFORWATIOU 12V to 5V at 5A VIN R1 8V TO 16V 15k C3 C1 C5 10µF 10µF VIN fADJ 100pF VOUT 25V 25V 5V AT 5A EFFICIENCY = 90% EXTVCC VOUT + C4 FCB LTM4602HV VOSET RSET C222µF 363.30VµF 13.7k RUN/SOFT-START RUN/SS SVIN 1% COMP PGOOD OPEN DRAIN SGND PGND 4602HV F24 12V TO 5V AT 5A WITH fADJ = 15k C1, C3: TDK C3216X5R1E106MT LTM4602HV MINIMUM ON-TIME = 100ns C2: TAIYO YUDEN, JMK316BJ226ML LTM4602HV MINIMUM OFF-TIME = 400ns C4: SANYO POS CAP, 6TPE330MIL VIN 5V TO 24V + C15IN0µF C1×02INµF BULK CER VIN (MULTIPLE PINS) GND EXTVCC VOUT VOUT 10C03pF fSAVDIJN (MULTIPLE PINS) C22OµUFT1 + C33O0UµT2F 6.3V VOUT VOSET LTM4602HV REFER TO REFER TO COMP TABLE 2 TABLE 2 FCB RSET PGOOD RUN/SS 0.6V TO 5V 66.5k C4 REFER TO OPT SGND TABLE 1 PGND REFER TO STEP DOWN (MULTIPLE PINS) RATIO GRAPH GND 4602HV F22 Figure 22. Typical Application, 5V to 24V Input, 0.6V to 6V Output, 6A Max 4602hvf 19

LTM4602HV TYPICAL APPLICATIOU Parallel Operation and Load Sharing VIN 4.5V TO 24V VOUT = 0.6V (cid:127) ([100k/N] + RSET)/RSET C8 WHERE N = 2 10µF 35V VIN fADJ EXTVCC VOUT + C9 C10 FCB VOSET 22µF 330µF LTM4602HV RSET 4V 15.8k RUN SVIN 1% COMP PGOOD SGND PGND VOUT RUN/SOFT-START 2.5V 12A C3 C4 1305µVF VIN fADJ 220pF EXTVCC VOUT + C5 C2 FCB VOSET 22µF 330µF LTM4602HV 4V RUN SVIN R1 100k COMP PGOOD SGND PGND C3, C8: TAIYO YUDEN, GDK316BJ106ML 4602HV TA02 C2, C9: TAIYO YUDEN, JMK316BJ226ML-T501 C5, C10: SANYO POS CAP, 4TPE330MI Current Sharing Between Two LTM4602HV Modules 6 12VIN 2.5VOUT 12AMAX RE 4 A H S AL IOUT2 DU IOUT1 VI NDI 2 I 0 0 6 12 TOTAL LOAD 4602HV TA03 4602hvf 20

LTM4602HV PACKAGE DESCRIPTIOU aaa Z Y 15BSC X W 15BSC VIE P O T 4 9 LGA Package×4-Lead (15mm 15mm)ence LTM DWG # 05-05-1800) aaa Z2.72 – 2.92 PAD 14CORNER SUBSTRATE 0.27 – 0.37 DETAIL B NOTES:1. DIMENSIONING AND TOLERANCING PER ASME Y14.5M-19 2. ALL DIMENSIONS ARE IN MILLIMETERS 3 LAND DESIGNATION PER JESD MO-222, SPP-010 4DETAILS OF PAD #1 IDENTIFIER ARE OPTIONAL,BUT MUST BE LOCATED WITHIN THE ZONE INDICATED.THE PAD #1 IDENTIFIER IS A MARKED FEATURE OR ANOTCHED BEVELED PAD 5. PRIMARY DATUM -Z- IS SEATING PLANE 6. THE TOTAL NUMBER OF PADS: 104 TOLERANCESYMBOLaaa0.150.10bbb0.15eee 10(Refer MOLDCAP 2.45 – 2.55DETAIL BZZ bbb PADSSEE NOTEST3 R P N M L KJ HG FEDC BA MYXeee LGA104 02-18 5689.6 2417.5 1920 21 22 23 24 49 60 71 82 93 104 0053.6 104 93 82 71 60 49 24 23 22 21 2019 212322 48 59 70 81 92 103 0080.5 103 92 81 70 59 48 20 2444.4 2471.3 1817 31 38 47 58 69 80 91 102 0018.3 AYOUT 102 91 80 69 58 47 38 31 1817 171918 820540000990...110 882554733166...300 576416 5.765091011 4.4950131415 2628293027 3633343537 414243454446 535557525456 646863656766 777879747576 888990858687 96979899100101 00550007701711782332.....31001000000440550...220 UGGESTED SOLDER PAD LTOP VIEW 12.70BSC 96979899100101 858687888990 747576777879 636465666768 525354555657 414243444546 3334353637 2627282930 131415 11109 167654 79111315681012141613.93BSCBOTTOM VIEW 8544.4 8517.5 32 2.3600 1.0900 40 51 62 73 84 95 0080.5 S 95 84 73 62 51 40 32 354 39 50 61 72 83 94 0053.6 94 83 72 61 50 39 2 1249.6 1 8 12 25 32 32 25 12 8 1 1 6.9888 6.5475 5.2775 4.0075 2.7375 1.4675 0.31750.00000.3175 1.2700 2.5400 4.4450 5.7150 6.9850 0.11 – 0.27 13.97BSC C(0.30)PAD 1 4602hvf 21

LTM4602HV PACKAGE DESCRIPTIOU Pin Assignment Tables (Arranged by Pin Number) PIN NAME PIN NAME PIN NAME PIN NAME PIN NAME PIN NAME PIN NAME PIN NAME A1 - B1 VIN C1 - D1 VIN E1 - F1 VIN G1 PGND H1 - A2 - B2 - C2 - D2 - E2 - F2 - G2 - H2 - A3 VIN B3 - C3 - D3 - E3 - F3 - G3 - H3 - A4 - B4 - C4 - D4 - E4 - F4 - G4 - H4 - A5 VIN B5 - C5 - D5 - E5 - F5 - G5 - H5 - A6 - B6 - C6 - D6 - E6 - F6 - G6 - H6 - A7 VIN B7 - C7 - D7 - E7 - F7 - G7 - H7 PGND A8 - B8 - C8 - D8 - E8 - F8 - G8 - H8 - A9 VIN B9 - C9 - D9 - E9 - F9 - G9 - H9 PGND A10 - B10 - C10 VIN D10 - E10 VIN F10 - G10 - H10 - A11 VIN B11 - C11 - D11 - E11 - F11 - G11 - H11 PGND A12 - B12 - C12 VIN D12 - E12 VIN F12 - G12 - H12 - A13 VIN B13 - C13 - D13 - E13 - F13 - G13 - H13 PGND A14 - B14 - C14 VIN D14 - E14 VIN F14 - G14 - H14 - A15 fADJ B15 - C15 - D15 - E15 - F15 - G15 - H15 PGND A16 - B16 - C16 - D16 - E16 - F16 - G16 - H16 - A17 SVIN B17 - C17 - D17 - E17 - F17 - G17 - H17 PGND A18 - B18 - C18 - D18 - E18 - F18 - G18 - H18 - A19 EXTVCC B19 - C19 - D19 - E19 - F19 - G19 - H19 - A20 - B20 - C20 - D20 - E20 - F20 - G20 - H20 - A21 VOSET B21 - C21 - D21 - E21 - F21 - G21 - H21 - A22 - B22 - C22 - D22 - E22 - F22 - G22 - H22 - A23 - B23 COMP C23 - D23 SGND E23 - F23 RUN/SS G23 FCB H23 - PIN NAME PIN NAME PIN NAME PIN NAME PIN NAME PIN NAME PIN NAME PIN NAME J1 PGND K1 - L1 - M1 - N1 - P1 - R1 - T1 - J2 - K2 - L2 PGND M2 PGND N2 PGND P2 VOUT R2 VOUT T2 VOUT J3 - K3 - L3 - M3 - N3 - P3 - R3 - T3 - J4 - K4 - L4 PGND M4 PGND N4 PGND P4 VOUT R4 VOUT T4 VOUT J5 - K5 - L5 - M5 - N5 - P5 - R5 - T5 - J6 - K6 - L6 PGND M6 PGND N6 PGND P6 VOUT R6 VOUT T6 VOUT J7 - K7 PGND L7 - M7 - N7 - P7 - R7 - T7 - J8 - K8 L8 PGND M8 PGND N8 PGND P8 VOUT R8 VOUT T8 VOUT J9 - K9 PGND L9 - M9 - N9 - P9 - R9 - T9 - J10 - K10 L10 PGND M10 PGND N10 PGND P10 VOUT R10 VOUT T10 VOUT J11 - K11 PGND L11 - M11 - N11 - P11 - R11 - T11 - J12 - K12 - L12 PGND M12 PGND N12 PGND P12 VOUT R12 VOUT T12 VOUT J13 - K13 PGND L13 - M13 - N13 - P13 - R13 - T13 - J14 - K14 - L14 PGND M14 PGND N14 PGND P14 VOUT R14 VOUT T14 VOUT J15 - K15 PGND L15 - M15 - N15 - P15 - R15 - T15 - J16 - K16 - L16 PGND M16 PGND N16 PGND P16 VOUT R16 VOUT T16 VOUT J17 - K17 PGND L17 - M17 - N17 - P17 - R17 - T17 - J18 - K18 - L18 PGND M18 PGND N18 PGND P18 VOUT R18 VOUT T18 VOUT J19 - K19 - L19 - M19 - N19 - P19 - R19 - T19 - J20 - K20 - L20 PGND M20 PGND N20 PGND P20 VOUT R20 VOUT T20 VOUT J21 - K21 - L21 - M21 - N21 - P21 - R21 - T21 - J22 - K22 - L22 PGND M22 PGND N22 PGND P22 VOUT R22 VOUT T22 VOUT J23 PGOOD K23 - L23 - M23 - N23 - P23 - R23 - T23 - 4602hvf 22

LTM4602HV PACKAGE DESCRIPTIOU Pin Assignment Tables (Arranged by Pin Number) PIN NAME PIN NAME PIN NAME PIN NAME G1 PGND P2 V A3 V A15 f OUT IN ADJ P4 V A5 V H7 PGND OUT IN A17 SV P6 V A7 V IN H9 PGND OUT IN H11 PGND P8 VOUT A9 VIN A19 EXTVCC P10 V A11 V H13 PGND OUT IN A21 VOSET P12 V A13 V H15 PGND OUT IN P14 V B23 COMP H17 PGND OUT B1 V P16 VOUT IN D23 SGND J1 PGND P18 VOUT C10 VIN K7 PGND P20 VOUT C12 VIN F23 RUN/SS K9 PGND P22 VOUT C14 VIN G23 FCB K11 PGND R2 VOUT D1 VIN J23 PGOOD K13 PGND R4 V OUT E10 V K15 PGND R6 V IN OUT E12 V K17 PGND R8 V IN OUT E14 V IN R10 V L2 PGND OUT L4 PGND R12 VOUT F1 VIN R14 V L6 PGND OUT R16 V L8 PGND OUT R18 V L10 PGND OUT R20 V L12 PGND OUT R22 V L14 PGND OUT L16 PGND T2 V OUT L18 PGND T4 V OUT L20 PGND T6 V OUT L22 PGND T8 V OUT T10 V M2 PGND OUT T12 V M4 PGND OUT T14 V M6 PGND OUT T16 V M8 PGND OUT T18 V M10 PGND OUT T20 V M12 PGND OUT T22 V M14 PGND OUT M16 PGND M18 PGND M20 PGND M22 PGND N2 PGND N4 PGND N6 PGND N8 PGND N10 PGND N12 PGND N14 PGND N16 PGND N18 PGND N20 PGND N22 PGND 4602hvf Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, 23 no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.

LTM4602HV TYPICAL APPLICATIOU 1.8V, 5A Regulator VIN 4.5V TO 24V C1 C5 1305µVF VIN fADJ 100pF VOUT 1.8V AT 6A EXTVCC VOUT + C4 FCB VOSET C223µF 330µF LTM4602HV R1 4V 100k RUN SVIN COMP PGOOD PGOOD SGND PGND RSET C1: TAIYO YUDEN, GMK316BJ106ML 49.9k C3: TAIYO YUDEN, JMK316BJ226ML-T501 4602HV TA04 1% C4: SANYO POS CAP, 4TPE330MI RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LTC2900 Quad Supply Monitor with Adjustable Reset Timer Monitors Four Supplies; Adjustable Reset Timer LTC2923 Power Supply Tracking Controller Tracks Both Up and Down; Power Supply Sequencing LT3825/LT3837 Synchronous Isolated Flyback Controllers No Optocoupler Required; 3.3V, 12A Output; Simple Design LTM4600 10A DC/DC µModule 10A Basic DC/DC µModule LTM4601 12A DC/DC µModule with PLL, Output Tracking/ Synchronizable, PolyPhase® Operation to 48A, LTM4601-1 Version has no Margining and Remote Sensing Remote Sensing, Fast Transient Response LTM4603 6A DC/DC µModule with PLL and Output Tracking/ Synchronizable, PolyPhase Operation, LTM4603-1 Version has no Remote Margining and Remote Sensing Sensing, Fast Transient Response Polyphase is a registered trademark of Linear Technology Corporation. This product contains technology licensed from Silicon Semiconductor Corporation. ® 4602hvf 24 Linear Technology Corporation LT 0107 • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com © LINEAR TECHNOLOGY CORPORATION 2007